Bought mainly for event photography in low light, but also testing with Canon 70-200 f/4L (with Sigma MC11 adapter)* for birds and squirrels through windows and sliding doors. Really enjoying using the Canon/Sigma adapter combination. Before this camera the 70-200 was napping in the closet, largely unused. I think it worked so well last night because I didn't have busy backgrounds like leafy trees behind moving birds. I just can't rely on autofocus outside for wildlife, anything busy looking or moving and will have to use peaking and manual focus, which isn't super fast...and leave my bird photography to other cameras. The 70-200 f/2.8 Sony lens is simply too expensive and too heavy. A possible alternative is the Tamron 70-180 but I don't really NEED it! It's lighter and costs way less, but is not cheap at $1200.

*Update: About the MC11 adapter - don't bother with it. The autofocus it afforded me with my adapter Canon lenses with more non-existent than not. If you look for MC11 used adapter they're going for very little money - and that is a clue that that it's not worth it.